Existing circuit-switched telecommunications networks, for example the international public switched telephone network (PSTN), are typically configured so that equipment (such as switches) in the transmission or bearer network, which carries user traffic (voice and data signals), is co-located with equipment (such as signalling points) in the associated signalling network, which carries control signals for co-ordinating the operation of the bearer network.
However, attention is now being directed to the possibility of telecommunications networks comprising distributed telecommunications switches, in which there is a separation of the switching/adaptation functionality from the signalling functionality. Furthermore, consideration is being given to the possibility of connecting dissimilar such networks (i.e. networks relying on different bearer technologies and/or signalling protocols).
Dissimilar telecommunications networks are typically interconnected via a “gateway” which provides the necessary conversions or adaptations between the bearer traffic and signalling protocol in each of the networks. In such an architecture control devices such as Media Gateway Controllers can be physically remote from the adaptation devices, such as Media Gateways. Media Gateway Controllers (also referred to as call agents or softswitches) can communicate with the Media Gateways they control using protocols such as Simple Gateway Control Protocol (SGCP), Media Gateway Control Protocol (MGCP—IETF RFC 2705), and the Megacop/H.248 protocol currently being defined. Media Gateway Controllers communicate with each other using extensions of current Call Control protocols such as Signalling System No.7 ISDN User Part (SS7 ISUP), Session Initiation Protocol (SIP—IETF RFC 2543), or ITU Recommendation H.323. New protocols may be defined for this interface in the future.
Protocol monitoring applications, such as tracing across a signalling network the protocol messages associated with a call, or building Call Data Records (CDRs) to summarise the key parameters relating to a call, require the ability to correlate across different protocols, which may refer to a single entity in multiple different, inconsistent ways. It is an object of this invention to facilitate such correlation.